\tracingonline=2
\tracingcommands=2
\tracingmacros=2
\tracingrestores=2

\catcode`{=1
\catcode`}=2

\prevgraf=2

{
    \showthe\prevgraf
    
    \prevgraf=5
}

\showthe\prevgraf

\showthe\inputlineno
\inputlineno=2

\showthe\inputlineno

\lastpenalty=5

\showthe\lastpenalty

\badness=5

\showthe\badness

\lastkern=2pt

\showthe\lastkern
\dimen0=\lastkern
\showthe\dimen0

\lastskip=2pt

\showthe\lastskip
\skip0=\lastskip
\showthe\skip0
\muskip0=\lastskip
\showthe\muskip0

%spacefactor

\par\showthe\spacefactor

\par\spacefactor=1

aa\showthe\spacefactor

aa\spacefactor=1\showthe\spacefactor

\hbox{\showthe\spacefactor=1}
\hbox{\spacefactor=1}

A\showthe\spacefactor

aA\showthe\spacefactor

Aa\showthe\spacefactor

a()\showthe\spacefactor

\end
